Thursday, 6 June 2013

Cosmic Rays Risk to Astronauts Going to Mars

Galactic cosmic rays and high-energy solar particles, recorded aboard NASA's Curiosity rover during its 8½-month interplanetary cruise, will give future astronauts a significant — but not excessive — dose of radiation on a round-trip journey to Mars.

Ever since Victor Hess discovered cosmic rays in 1912, scientists have come to realize that space radiation is one of the most formidable hazards during long-duration space travel. A typical astronaut aboard the International Space Station, even while protected by the craft's outer hull and Earth's magnetosphere, absorbs as much radiation in a six-month stay as we ground-dwellers do in 20 years. Head deeper into space — say, on a mission to a nearby asteroid or to Mars — and the risks are magnified considerably.

Curiosity's Radiation Assessment Detector (RAD) measured the intensity of cosmic rays and solar energetic particles during the spacecraft's long cruise to Mars.

NASA / JPL

Plenty of craft have monitored space radiation over the years, but those detectors were completely unprotected in order to get "raw" measurements. Now, however, researchers finally have an idea of how much an astronaut would get zapped inside a reasonably well-shielded spacecraft cruising through the inner solar system.

The findings come from the Radiation Assessment Detector (RAD) that took an 8½-month ride to Mars aboard NASA's Curiosity rover. During that long cruise, RAD was installed inside Curiosity, which in turn was sandwiched inside a coccoon-like aeroshell with the rocket-propelled descent stage over it and a thick heat shield below it. This gave RAD shielding from space radiation much like what NASA engineers are building into the forthcoming Orion crew capsule.